Chimney cap construction



July 28, 1953 R. F. VAN ALSTYNE CHIMNEY CAP CONSTRUCTION- Filed Jan. 28, 1950 INVENTOR. 1?. E lflAMZS/Wf MVL ZM'M W ATTORNEY Patented July 28, 1953 UNITED JSTATE' \"ATENT OFFICE CHIMNEY'CAP CONSTRUCTION I I Richard Ryan Alstyne', Davenport, Iowa s, 1950, Serial No. 141,140

- Application anuary 2 to provide increased resistance to the corrosive effects of flue gases: particularly the 'sulphurous and sulphuricacid components thereof. It is a --further feature ofthis-"invention toprovide a chimney cap construction which improves the natural draft of the chimney by making use of air currents passing the chimney for drawing out flue gases from the upper end of the chimney. Another feature of this invention is the provision of a chimney cap construction which includes a cap member having a downwardly depending conoidal center section shaped so as to cause the escaping flue gases to pass outwardly in a smooth, unbroken, streamline flow, thereby avoiding eddying currents and gas pockets that might retard the outward movement of the flue gases. My invention further resides in the combination, construction, and arrangement of parts illustrated in the accompanying drawings and, while I have shown therein what is now regarded as the preferred embodiment of this invention, I desire the same to be understood as illustrative only and not to be interpreted in a limiting sense.

In the drawings annexed hereto and forming a part hereof,

Fig. 1 is a fragmentary plan view of a chimney cap construction in which the principles of the present invention have been incorporated; and

Fig. 2 is a sectional view along the plane indicated by the line 2-2 of Fig. 1.

Referring now to the drawings, the top of the chimney I is provided with an upstanding ridge 2 and centrally has a flue lining 3 arranged to extend above the upper end of the chimney I. Fixed in any suitable manner to the upper end of the chimney I is a base member 5 which preferably comprises an annular part in the form of a ring member made of vitreous enamel so as to resist the corrosive action of the acids in the flue gases, such as sulphurous or sulphuric acids. The base member 5 has a groove 6 on its lower side to receive the ridge 2 and, preferably, the internal diameter of the base member is such as to snugly receive the upper end of the flue lining 3, as shown in Fig. 2. The base member 5 may be cemented to the top of the chimney I or secured thereto in any other suitable way. As shown in Fig. 2, the cap comprises the ring member 5 and the cap member 8, held spaced from each other by the posts [6.

;1 Claim. (01. 98-83) A cap member 8 is carried above the base member 5 and is preferably in the form of a disk-like part having an upper convex surface 9 and a lower surface Ill whichis partially concave, as indicatedat I I but centrally is provided with a downwardly extending conoidal section I2, the apex I 5 of which is disposed axially of the base member 5,,the axis of the conoidal section I2 containing the center of curvature of the outer convex surface 9. Preferably, the apex !3 extends down into the central opening IA of the base member 5.

A plurality of metal pegs I6 are embedded at their lower ends into the upper part of the base member 5 and at their upper ends into the peripherally outer portions of the cap member 8 and serve as means for supporting the cap member 8 on the base member 5. It will be seen from Fig. 2 that the upwardly and outward- 1y flaring walls of the conoidal portion I2 extend outwardly and join the downwardly and outwardly flaring walls II in a smooth curve. It will also be noted that the lower walls II are joined with the peripherally outer portions of the upper convex surface 9 in a thin section H, the edge of which is rounded to form a drip ring 18 which lies outwardly of the upper side of the base member 5. Rain water dripping from the edge of the cap member 8 does not, therefore, run into the inside of the base member 5.

Upwardly moving flue gases pass outwardly of the chimney through the space between the cap 5 and the base 5, being guided in this movement by the curved walls II and I2, which cause the moving gases to have a smooth, unbroken, streamline flow. There are no pockets which might cause eddying currents or which might retard the smooth flow of the products of combustion from the chimney. The natural draft of the chimney is aided by any horizontally moving air currents past the chimney cap, the air foil section of the cap member resulting in a zone of lowered pressure at the down wind side of the chimney cap, particularly in the space between the cap 8 and the base ring 5. The round configuration of the cap and base contribute to this result, also.

It is of course understood that the specific description of structure set forth above may be departed from without departing from the spirit of my invention as disclosed herein and as de fined in the appended claim.

Having now described my invention, I claim: A chimney cap construction comprising a molded annular base member, a disk-like cap member having an upper convex surface and a 3 lower downwardly extending conoidal surface, said surfaces being joined at their outer peripheral portions forming a thin edge, and said lower surface being shaped so as to extend upwardly and radially outwardly from the apical center of said lower conoidal surface to points lying above but radially inwardly of said peripherally positioned thin edge, and thence downwardly and radial'ly outwardly to points merging with said thin edge, thereby presenting to a transverse air current a downwardly facing sub! stantially annular surface having a positive or upward camber, said thin edge lying in a su-b stantially horizontal plane and, saidlower surface extending from said apical center upwardly and outwardly in a smooth curve and intersecting said plane at points lying approximately midway. radially inwardly from the outer circumference of said thin edge to the vertical axis of said apical center, whereby said lower; surface radially outwardly ofsaid points of intersection extends upwardly of said plane andthen downwardly relative thereto to their juncture with said thin edge, and means for supporting said cap member above said base member such a distance that the downwardly extending apex of said conoidal surface lies adjacent the horizontal plane of the upper end ofsaid annular basemember, whereby movement of air currents an approximately horizontal direction can pass across said cap member, both below as well as above the latter, which serves to draw flue gases out of the chimney through the space between said base member and said cap member at the downwind side of the chimney.

RICHARD F: ALSTYNE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 238,135 Noorden Feb. 22, 1881 605,508 Pancoast June 14, 1898 715,169; Stanley Dec. 2, 1902 H0247 Cross Sept. 29, 1903 1,073,079 Christie Sept. 9, 1913 1,531,831 Bartholdi Mar. 31, 1925 1 ,955,176 Bearing Apr. 17.11934 23358042- Zimmerman Sept; 12;.19144 FOREIGN RATENTS,

Number Country Date 263; Denmark Nov; 11 1895 1359716 Great Britain Dec. 19:19 372,079; Germany 2,4,,1923 232322; Switzerland, Mar 3 5, 19 

